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Factsheet – An on-line tool to evaluate groundwater sustainability in the Upper Wabash basin

A research project funded by the Indiana Water Resources Research Center through the U.S. Geological Survey’s 104B annual base grants (section 104 of the Water Resources Research Act of 1984, as amended).

Start Date: 2021-09-01

End Date: 2022-08-31

Total Federal Funds: $24,304

Total Non-Federal Funds: $54,779

The state of Indiana does not experience wide-spread water scarcity as water resources are currently sufficient. It receives more than 1000 mm of precipitation each year and out of that, in some areas more than 250 millimeters recharge groundwater aquifers. As a result, groundwater resources have traditionally provided a buffer for cities and farms against drought. However, agricultural intensification and changing weather patterns mean that groundwater conflicts and ecosystem impacts during times of drought are increasing, and adaptation and adaptable management of water resources may be needed even in areas that are traditionally water abundant such as Indiana.

In order to quantify how increasing trends in groundwater withdrawals impact water availability, a simulation tool that can integrate changes in groundwater storage is needed. This project will quantify variation in groundwater resources considering alterations in projected recharge and demand to determine whether a sufficient volume of water will be available when and where it is needed.

Research Objectives

1. Quantify groundwater withdrawals in Indiana through 2060 by sector for different future climate scenarios.

 

2. Quantify variability in aquifer storage and streamflow response for different future water use scenarios.

 

3. Disseminate research outcomes via an interactive website, presentations, and publications.

Indiana Waters Website
Screenshot of the State of Indiana Waters website (https://iwrrc.org/indiana-water/) showing historic trends in groundwater level superimposed on a heat map of significant water withdrawals. The proposed work will add layers for future water trends.

Researcher Profile

Dr. Laura Bowling

Principal Investigator Dr. Laura Bowling is a Professor of Agronomy at Purdue University.

Dr. Keith Cherkauer

Co-Principal Investigator Dr. Keith Cherkauer is a Professor in the Department of Agricultural & Biological Engineering at Purdue University.

Major Conclusions & Significance

Total groundwater withdrawals in Indiana are projected to increase in the coming decades due to changes in both socio-economic and climatic drivers. Projection of groundwater withdrawals revealed the following:

  • Water withdrawals per person, per unit output, and per irrigated area are projected to decrease for all water use sectors except for aquaculture, which increased by 47%. The greatest decline in groundwater withdrawals per demand unit was for the industrial and commercial (IC) sector (-89%).
  • State-total projected withdrawals in 2060 are 20% greater than 2015 for climatic projection considering the RCP 4.5 emissions scenario and 22% greater for the RCP 8.5 scenario. The projected withdrawals for 2060 are 7.5% (RCP 4.5) and 9.2% (RCP 8.5) more when climate influence is represented compared to when it was not explicitly represented.
  • There were both projected increases and decreases for 2060 withdrawals when compared to observed 2015 withdrawals for individual counties, ranging from -33% to 96%. The greatest increases were projected in central and Southern Indiana, where population increase is predicted to be the greatest.

The Variable Infiltration Capacity Groundwater (VICGW) model allows representation of both future water supply and demand, revealing some local scale and seasonal areas of concern:

  • Mean annual runoff in the Wabash River basin is projected to increase by 10% for the period from 2041-2070 under RCP 4.5 and by 12% for RCP 8.5, primarily due to increasing precipitation.
  • In contrast, there is a projected decrease in mean annual runoff from the base scenario due to change in demand. These demand-changes represent -8.2% and -6.7%, respectively, of the projected combined changes.
  • Under both RCP 4.5 and RCP 8.5, the mean monthly streamflow is predicted to increase in the winter and spring and decrease in the summer and fall because of changes in supply.
  • On a regional level, the impact of demand on streamflow was low, however baseflow decreased slightly.
  • Mean water table positions are not projected to change much, however the annual maximum water table depth (end of growing season) is projected to increase by up to 2 m in some locations.

What Does This Mean For Indiana?

Adaptation and sustainable management of water resources requires that policy makers have better quantification of the long-term impacts of human alterations. The VICGW model allows representation of both future water supply and demand. It provides a mechanism to identify potential areas of concern for future groundwater development utilizing a water balance approach to constrain future water availability, but without the intensive data and computational requirements of a groundwater transport model. In the future, this tool could be adapted to allow Department of Natural Resources personnel to evaluate the impact of significant water withdrawal facilities as part of a permitting process. The development of seven different scenarios to evaluate the impact of projected demand, projected supply, and their interaction on hydrologic cycle parameters such as streamflow and water table positions provide more comprehensive information than previously available on possible future water needs in Indiana. This can benefit on-going state-wide efforts for water resources planning such as the Regional Water Studies being completed by the Indiana Finance Authority (https://www.in.gov/ifa/regional-water-studies/regional-water-studies-overview/).

Training The Next Generation

One of the missions of the Indiana Water Resources Research Center, and all Water Centers, is to train the next generation of water scientists. This project successfully funded research for one Ph.D. student within Dr. Bowling’s lab.

 

Contact Laura Esman, Managing Director, to request a printed copy of this factsheet.

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